Low molecular weight hydroxyaminomethylphosphonates have been described in the literature as seen by the following publications:
1. M. P. Osipova et al., Deposited Doc. SPSTL 232 khp-D80 (USSR); Chem. Abst. 97, 110110 (1982); PA1 2. K. A. Petrov et al., Zh. Obshch. Khim, 49, 590 (1979); PA1 3. M. S. Skorobogatova et al., Izv. Akad. Nauk. SSSR, Ser. Khim. 1979, 1867; PA1 4. A. Muktarov et al., Izv. Akad. Nauk. SSSR, Ser. Khim. 1976, 2816; PA1 5. A. Alberti et al., Tetrahedron, 40, 4955 (1984); PA1 6. J. M. J. Tronchet et al., Carbohydrate Research, 136, 375 (1985); PA1 7. A. Vasella et al., Helv. Chim. Acta, 68, 1730 (1985); and PA1 8. Y. Yamada et al., Tetrahedron Letters, 29, 663 (1988). PA1 R.sub.2 and R.sub.3 are independently hydrogen, alkyl of 1 to 36 carbon atoms, aryl of 6 to 10 carbon atoms, or phenylalkyl of 7 to 15 carbon atoms, PA1 R.sub.4 and R.sub.5 are independently hydrogen, alkyl of 1 to 36 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, aryl of 6 to 10 carbon atoms, said aryl substituted by one or two alkyl of 1 to 8 carbon atoms or phenylalkyl of 7 to 15 carbon atoms, or an alkali metal or alkaline earth metal salt, and PA1 R.sub.6 is alkyl of 1 to 36 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, aryl of 6 to 10 carbon atoms, said aryl substituted by one or two alkyl of 1 to 8 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, or is a group of formula II ##STR3## wherein R.sub.2, R.sub.3, R.sub.4 and R.sub.5 have the meanings given above. PA1 R.sub.1 is hydrogen, alkyl of 4 to 18 carbon atoms, cycloalkyl of 5 to 7 carbon atoms, phenyl or phenyl substituted by alkyl of 1 to 4 carbon atoms, or benzyl, or R.sub.1 is (R)(R')(R")Si-- or (R)(R')(R")Si--OCH.sub.2 -- where R, R' and R" are independently alkyl of 1 to 4 carbon atoms or phenyl, PA1 R.sub.2 and R.sub.3 are independently hydrogen, alkyl of 1 to 17 carbon atoms or phenyl, PA1 R.sub.4 and R.sup.5 are independently hydrogen, alkyl of 1 to 18 carbon atoms, cycloalkyl of 5 to 7 carbon atoms, phenyl or phenyl substituted by alkyl of 1 to 4 carbon atoms, or benzyl, and PA1 R.sub.6 is alkyl of 4 to 18 carbon atoms, benzyl or is a group of formula II where R.sub.2, R.sub.3, R.sub.4 and R.sub.5 have the preferred meanings given above. PA1 R.sub.1 is hydrogen or alkyl of 4 to 12 carbon atoms, or R.sub.1 is (R)(R')(R")Si-- or (R)(R')(R")Si--OCH.sub.2 -- where R, R' and R" are independently methyl, tert-butyl or phenyl, PA1 R.sub.2 is hydrogen or methyl, PA1 R.sub.3 is hydrogen, alkyl of 1 to 17 carbon atoms or phenyl, PA1 R.sub.4 and R.sub.5 are independently hydrogen, alkyl of 1 to 18 carbon atoms, phenyl or benzyl, and PA1 R.sub.6 is alkyl of 4 to 18 carbon atoms, benzyl or a group of formula II where R.sub.2, R.sub.3, R.sub.4 and R.sub.5 have the most preferred meanings given above. PA1 R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are as defined above. PA1 R.sub.2 and R.sub.3 are independently hydrogen, alkyl of 1 to 36 carbon atoms, aryl of 6 to 10 carbon atoms or phenylalkyl of 7 to 15 carbon atoms, PA1 R.sub.4 and R.sub.5 are independently alkyl of 12 to 36 carbon atoms, and PA1 R.sub.6 is alkyl of 12 to 36 carbon atoms, benzyl or a group of formula II where R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are as defined above. PA1 R.sub.2 and R.sub.3 are independently hydrogen, alkyl of 1 to 17 carbon atoms or phenyl, PA1 R.sub.4 and R.sub.5 are independently alkyl of 12 to 18 carbon atoms, and PA1 R.sub.6 is alkyl of 12 to 18 carbon atoms, benzyl or a group of formula II where R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are as defined above.
U.S. Pat. No. 3,933,946 describes N-hydroxy-N-phosphonomethylglycine esters which are useful as herbicides and plant growth regulators.
The use of hydroxyaminomethylphosphonates as stabilizers for organic materials is not described or suggested in the prior art. Additionally the compounds of formula I where R.sub.4, R.sub.5 and R.sub.6 are alkyl having at least 12 carbon atoms are novel. The instant compounds where R.sub.1 is a substituted silyl moiety are also novel.